As a conventional liquid crystal display device, for example, the device disclosed in Japanese Unexamined Patent Application Publication No. 2008-203444 is known. The liquid crystal display device includes a backlight, a liquid crystal panel illuminated by the backlight, a frame accommodating the backlight and the liquid crystal panel, a light-shielding adhesive tape with which the backlight is bonded to the frame and that prevents light from the backlight from leaking to surroundings, and a double-sided adhesive tape with which the liquid crystal panel is bonded to the frame. Using the double-sided adhesive tape, other than the light-shielding adhesive tape, which is used to bond the liquid crystal panel to the frame, makes it easy to replace the liquid crystal panel without damaging the backlight and the like.
In the liquid crystal display device, the light-shielding adhesive tape also functions to fix various types of optical films (optical sheets) arranged on the liquid crystal panel side of the backlight. The light-shielding adhesive tape and the double-sided adhesive tape with which the liquid crystal panel is bonded to the frame surround the gap between the optical sheet and the liquid crystal panel to form an enclosed space. Accordingly, when these members are bonded, the optical sheet may be deflected by an air-lock in the enclosed space, resulting in sticking to the liquid crystal panel. When the optical sheet contracts or expands due to some reason after being bonded, a similar trouble sometimes occurs. As a result, luminance unevenness occurs or a concentric stripe pattern called Newton's rings appears in the liquid crystal display device.
With a reduction in the thickness of a liquid crystal display device, the gap between an optical sheet and a liquid crystal panel further decreases. In addition, the optical sheet itself tends to decrease in thickness. Accordingly, such a problem may become more conspicuous.